1. Field of the Invention
This invention relates generally to scuba gear, and is more particularly concerned with light weight scuba gear having an automatic buoyancy control.
2. Discussion of the Prior Art
Self contained breathing apparatus is well known in the art. Such apparatus has been well developed for use under water, and the development and use have been extended to numerous environments including the smoke and gas filled atmosphere of fire fighting, and the gas filled atmosphere of chemical processing, gas leaks and the like. Since the apparatus is to be carried by a person, it is of course desirable to have the apparatus as light in weight as possible without undue sacrifice of air capacity. Thus, there has been developed a light-weight pressure vessel for use in smoke, chemical and similar environments. The light-weight pressure vessels comprise relatively thin-walled aluminum cylinders wrapped with fibers, the fibers being embedded in a binder resin such as epoxy. These light-weight pressure vessels are capable of withstanding higher pressures than the usual aluminum cylinders, so they can hold a greater quantity of air. The disadvantage of the light-weight pressure vessels is that, because of concern about long-term compatibility with water, the United States Department of Transportation has not approved fiber wrapped pressure vessels for underwater use. Thus, scuba gear has been unable to take advantage of such vessels, or "tanks" as they are called in scuba application.
Scuba gear typically includes a buoyancy adjusting means so that, once a diver is in the water, the diver's buoyancy can be adjusted to neutral so it will be easy for the diver to move up or down in the water. Of course, the buoyancy can be adjusted to increase the buoyancy for a diver to rise from the depths. The problem with the conventional buoyancy control is that the high pressure at great depths compresses the air in the buoyancy control device and makes the device smaller, thereby decreasing the amount of buoyancy. Conversely, when the diver rises in the water, the lower ambient pressure allows the buoyancy device to expand, thereby increasing the amount of buoyancy. As a result, the diver must continually adjust the air in the buoyancy device in order to retain the desired neutral buoyancy.